California Historical Building Code (CHBC)

The California Historical Building Code (CHBC) is Part 8 of the California Building Standards Code (Title 24, California Code of Regulations), also known as the State Historical Building Code. It provides alternative building regulations for the repair, alteration, rehabilitation, restoration, relocation and continued use of a qualified historical building or property, so that owners can meet fire, life-safety, seismic and accessibility goals without destroying the historic fabric that ordinary code prescriptions would require them to replace.

The 2025 CHBC is the current edition, effective January 1, 2026, replacing the 2022 edition. The code is authorized by California Health and Safety Code Sections 18950–18961 and administered through the Division of the State Architect, but it is permissive, not mandatory — a project elects to use it. Local jurisdictions adopt the statewide edition and may add amendments, and a building must first be a "qualified historical" resource. Determining eligibility and the right alternative is exactly what GoCodebook helps you reconcile.

The CHBC addresses the same safety subjects as the regular code — use and occupancy, means of egress, fire protection, structural and seismic design, accessibility, and mechanical, plumbing and electrical systems — but supplies alternative provisions tailored to historic construction. Instead of forcing modern prescriptive solutions, it lets a design professional demonstrate equivalent safety while keeping archaic materials and methods such as unreinforced masonry, lath-and-plaster, board sheathing and historic timber framing. The structural provisions live in the CHBC's structural chapter and have been used on URM, steel-and-masonry-infill and timber buildings for seismic strengthening and earthquake-damage repair.

A core concept is the "qualified historical building or property" — generally a building, site, structure, object or district listed or eligible for a national, state or local historic register or inventory. Only qualified resources may use the CHBC. The code is frequently the tool that makes adaptive reuse financially feasible, because it avoids triggering full modern upgrades that would gut a landmark. See where coverage is deepest.

For accessibility, the CHBC allows alternatives where strict application of CBC Chapter 11B would threaten or destroy historic significance — for example, by permitting alternate routes, equivalent facilitation or limited exceptions, while still maximizing access to the greatest extent feasible. This is a careful balance: the goal is meaningful access without erasing the historic character that made the building worth preserving.

For seismic and structural safety, the CHBC provides alternative performance-based regulations that recognize how historic buildings actually behave, rather than imposing new-construction demands. This is especially important for unreinforced masonry retrofit and for re-occupying long-vacant or damaged landmarks. The CHBC commonly works alongside the California Existing Building Code (Part 10), and a design team chooses the pathway that best preserves the resource while delivering equivalent safety.

Using the CHBC is optional and project-specific. An owner or design professional elects it, documents that the building is a qualified historical resource, and then proposes alternatives that the building official — often with input from the State Historical Building Safety Board — reviews for equivalent safety. Because it is discretionary and judgment-based, outcomes vary by jurisdiction and by how well the proposal is justified.

GoCodebook identifies the adopted edition, the relevant CHBC alternative provisions, and any local amendments, then returns the governing language with a citation so you can build a defensible compliance argument. Whether you are restoring a landmark theater, converting a historic warehouse, or seismically strengthening a URM building, the CHBC is usually the difference between a feasible adaptive-reuse project and a teardown.

California's adopted codes — including the California Historical Building Code (CHBC) — are published under Title 24 and hosted on code libraries such as UpCodes (up.codes) and ICC Digital Codes from the International Code Council (ICC). Those let you read the text section by section.

GoCodebook goes further: instead of searching a code library, you ask a question and get the controlling provision for the edition and local amendments your jurisdiction adopted, with a citation to verify. See how GoCodebook compares to UpCodes and ICC.